The extent to which viewing a 'virtual' limb, the mirror image of an intact limb, modifies the experience of a phantom limb, was investigated in 80 lower limb amputees before, during and after repeated attempts to simultaneously move both intact and phantom legs. Subjects were randomly assigned to one of two conditions, a control condition in which they only viewed the movements of their intact limb and a mirror condition in which they additionally viewed the movements of a 'virtual' limb. Although the mirror condition elicited a significantly greater number of phantom limb movements than the control condition, it did not attenuate phantom limb pain and sensations any more than the control condition. The potential of a 'virtual' limb as a treatment for phantom limb pain was discussed in terms of its ability to halt and/or reverse the cortical re-organisation of motor and somatosensory cortex following acquired limb loss.

The study demonstrates the need for further research to determine whether the results obtained regarding occupational changes following amputation result pain, disability, amputees' attitudes towards themselves in relation to work, or to employers' attitudes and beliefs about their capabilities. Further research is also required to determine why so few amputees make use of available services and why, even when they are used, such services are not perceived as being helpful. Finally, there is a need to clarify the relationship between the extent of daily prostheses use, the experience of phantom limb pain and employment status.

No abstract

Research suggesting that psychological factors play a role in phantom limb pain abounds in the literature. Despite recent research suggesting that these factors exacerbate rather than cause phantom limb pain, clinicians still frequently use personality as a rationale to explain amputees' phantom limb pain. The present study aimed to examine psychological distress in a working-age population of amputees not specifically seeking help for their pain. The study was conducted in two phases. Phase 1 included 315 amputees who completed the General Health Questionnaire (GHQ). Phase 2 included a subset of the original sample who completed the Beck Depression Inventory (BDI). In Phase 1, although over 50% of the sample reported GHQ scores over the threshold used to detect "caseness," this was not related to phantom limb pain. In Phase 2 of the study, only 15% of the sample reported moderate to severe symptoms of depression. Only 4% of the variance in phantom limb pain was accounted for using the overall BDI score. When BDI items were examined individually within regression models, a number significantly predicted phantom limb pain. However, the items most related to phantom limb pain were those involved in "performance difficulties" rather than "negative affect." The present study suggests that negative affect in amputees may be related to disability rather than pain.

123Two proteinases have been purified from cell extracts of the cellular slime mould Dictyostelium discoideurn and have been identified as proteinase E and proteinase B by electrophoretic analysis on polyacrylamide gels containing haemoglobin. Both were probably glycoproteins, each consisting of a single polypeptide chain with apparent molecular weights of 58 000 (proteinase E) and 30000 (proteinase B) as indicated by SDS-PAGE. A higher molecular weight of 38000 was suggested for proteinase B by gel filtration. On isoelectric focusing multiple forms of proteinase E were revealed with isoelectric points ranging from 3.05 to 3-35. There was only a single form of proteinase B with an isoelectric point at pH 3.55. Both enzymes hydrolysed proteins at low pH and activated trypsinogen at pH 3.5. Proteinase B had much lower activity than proteinase E and required a reducing agent such as DTT for maximum activity. The pH optimum for activity of proteinase E towards hide powder azure was 2.5. Proteinase B, but not proteinase E, also hydrolysed a number of derivatives of basic amino acids and related peptide derivatives. N-Benzoyl-or-DL-arginine P-naphttylamide (Bz-Arg-NNap) was used as substrate during purification, N-benzoyl-L-prolyl-L-phenylalanyl-L-arginine p-nitroanilide (Bz-Pro-Phe-Arg-Nan) was used for proteinase B characterization. Activity was optimal at pH 6 and was dependent on a reducing agent. Inhibitor studies indicated that proteinase E was probably a pepstatin-insensitive aspartic proteinase which was also inhibited by mercurials through binding to a cysteine residue not involved in the catalytic mechanism. Proteinase B was inactivated by a range of typical cysteine proteinase inhibitors. Proteinase B may be identical to proteinase I previously purified from D. discoideum. Overall the properties of both proteinases were consistent with their being involved in general protein degradation within the lysosomes of D. discoideum.